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Critical accounting estimates

The Group prepares its consolidated financial statements in accordance with IFRS as issued by the International Accounting Standards Board and IFRS as adopted by the European Union, the application of which often requires judgements to be made by management when formulating the Group’s financial position and results. Under IFRS, the directors are required to adopt those accounting policies most appropriate to the Group’s circumstances for the purpose of presenting fairly the Group’s financial position, financial performance and cash flows.

In determining and applying accounting policies, judgement is often required in respect of items where the choice of specific policy, accounting estimate or assumption to be followed could materially affect the reported results or net asset position of the Group should it later be determined that a different choice would be more appropriate.

Management considers the accounting estimates and assumptions discussed below to be its critical accounting estimates and, accordingly, provides an explanation of each below.

The discussion below should also be read in conjunction with the Group’s disclosure of significant IFRS accounting policies, which is provided in note 2 to the consolidated financial statements, “Significant accounting policies”.

Management has discussed its critical accounting estimates and associated disclosures with the Company’s Audit Committee.

Impairment reviews

IFRS requires management to undertake an annual test for impairment of indefinite lived assets and, for finite lived assets, to test for impairment if events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.

Impairment testing is an area involving management judgement, requiring assessment as to whether the carrying value of assets can be supported by the net present value of future cash flows derived from such assets using cash flow projections which have been discounted at an appropriate rate. In calculating the net present value of the future cash flows, certain assumptions are required to be made in respect of highly uncertain matters, including management’s expectations of:

  • growth in EBITDA, calculated as adjusted operating profit before depreciation and amortisation;
  • timing and quantum of future capital expenditure;
  • long term growth rates; and
  • the selection of discount rates to reflect the risks involved.

The Group prepares and internally approves formal five year plans for its businesses and uses these as the basis for its impairment reviews. In certain markets which are forecast to grow ahead of the long term growth rate for the market, further years will be used until the forecast growth rate trends towards the long term growth rate, up to a maximum of ten years.

For businesses where the first five years of the ten year management plan are used for the Group’s value in use calculations, a long term growth rate into perpetuity has been determined as the lower of:

  • the nominal GDP rates for the country of operation; and
  • the long term compound annual growth rate in EBITDA in years six to ten estimated by management.

For businesses where the full ten year management plans are used for the Group’s value in use calculations, a long term growth rate into perpetuity has been determined as the lower of:

  • the nominal GDP rates for the country of operation; and
  • the compound annual growth rate in EBITDA in years nine to ten of the management plan.

Changing the assumptions selected by management, in particular the discount rate and growth rate assumptions used in the cash flow projections, could significantly affect the Group’s impairment evaluation and, hence, results.

The Group’s review includes the key assumptions related to sensitivity in the cash flow projections. Further details are provided in note 10 to the consolidated financial statements.

Revenue recognition and presentation

Arrangements with multiple deliverables

In revenue arrangements including more than one deliverable, the deliverables are assigned to one or more separate units of accounting and the arrangement consideration is allocated to each unit of accounting based on its relative fair value.

Determining the fair value of each deliverable can require complex estimates due to the nature of the goods and services provided. The Group generally determines the fair value of individual elements based on prices at which the deliverable is regularly sold on a standalone basis, after considering volume discounts where appropriate.

Presentation: gross versus net

When deciding the most appropriate basis for presenting revenue or costs of revenue, both the legal form and substance of the agreement between the Group and its business partners are reviewed to determine each party’s respective role in the transaction.

Where the Group’s role in a transaction is that of principal, revenue is recognised on a gross basis. This requires revenue to comprise the gross value of the transaction billed to the customer, after trade discounts, with any related expenditure charged as an operating cost.

Where the Group’s role in a transaction is that of an agent, revenue is recognised on a net basis, with revenue representing the margin earned.


The Group’s tax charge on ordinary activities is the sum of the total current and deferred tax charges. The calculation of the Group’s total tax charge necessarily involves a degree of estimation and judgement in respect of certain items whose tax treatment cannot be finally determined until resolution has been reached with the relevant tax authority or, as appropriate, through a formal legal process. The final resolution of some of these items may give rise to material profits, losses and/or cash flows.

The complexity of the Group’s structure following its geographic expansion makes the degree of estimation and judgement more challenging. The resolution of issues is not always within the control of the Group and it is often dependent on the efficiency of the legal processes in the relevant taxing jurisdictions in which the Group operates. Issues can, and often do, take many years to resolve. Payments in respect of tax liabilities for an accounting period result from payments on account and on the final resolution of open items. As a result, there can be substantial differences between the tax charge in the consolidated income statement and tax payments.

Significant items on which the Group has exercised accounting judgement include a provision in respect of an enquiry from UK HMRC with regard to the CFC tax legislation (see note 33 to the consolidated financial statements), potential tax losses in respect of a write down in the value of investments in Germany (see note 6 to the consolidated financial statements) and litigation with the Indian tax authorities in relation to the acquisition of Vodafone Essar (see note 33 to the consolidated financial statements). The amounts recognised in the consolidated financial statements in respect of each matter are derived from the Group’s best estimation and judgement, as described above. However, the inherent uncertainty regarding the outcome of these items means eventual resolution could differ from the accounting estimates and therefore impact the Group’s results and cash flows.

Recognition of deferred tax assets

The recognition of deferred tax assets is based upon whether it is more likely than not that sufficient and suitable taxable profits will be available in the future, against which the reversal of temporary differences can be deducted.

Recognition, therefore, involves judgement regarding the future financial performance of the particular legal entity or tax group in which the deferred tax asset has been recognised.

Historical differences between forecast and actual taxable profits have not resulted in material adjustments to the recognition of deferred tax assets.


The amount of goodwill initially recognised as a result of a business combination is dependent on the allocation of the purchase price to the fair value of the identifiable assets acquired and the liabilities assumed. The determination of the fair value of the assets and liabilities is based, to a considerable extent, on management’s judgement.

Allocation of the purchase price affects the results of the Group as finite lived intangible assets are amortised, whereas indefinite lived intangible assets, including goodwill, are not amortised and could result in differing amortisation charges based on the allocation to indefinite lived and finite lived intangible assets.

On transition to IFRS, the Group elected not to apply IFRS 3, “Business combinations”, retrospectively as the difficulty in applying these requirements to the large number of business combinations completed by the Group from incorporation through to 1 April 2004 exceeded any potential benefits. Goodwill arising before the date of transition to IFRS, after adjusting for items including the impact of proportionate consolidation of joint ventures, amounted to £78,753 million.

If the Group had elected to apply the accounting for business combinations retrospectively, it may have led to an increase or decrease in goodwill and increase in licences, customer bases, brands and related deferred tax liabilities recognised on acquisition.

Finite lived intangible assets

Other intangible assets include the Group’s aggregate amounts spent on the acquisition of 2G and 3G licences, computer software, customer bases, brands and development costs. These assets arise from both separate purchases and from acquisition as part of business combinations.

On the acquisition of mobile network operators, the identifiable intangible assets may include licences, customer bases and brands. The fair value of these assets is determined by discounting estimated future net cash flows generated by the asset, where no active market for the assets exist. The use of different assumptions for the expectations of future cash flows and the discount rate would change the valuation of the intangible assets.

The relative size of the Group’s intangible assets, excluding goodwill, makes the judgements surrounding the estimated useful lives critical to the Group’s financial position and performance.

At 31 March 2009, intangible assets, excluding goodwill, amounted to £20,980 million (2008: £18,995 million) and represented 13.7% (2008: 14.9%) of the Group’s total assets.

Estimation of useful life

The useful life used to amortise intangible assets relates to the future performance of the assets acquired and management’s judgement of the period over which economic benefit will be derived from the asset. The basis for determining the useful life for the most significant categories of intangible assets is as follows:

Licences and spectrum fees

The estimated useful life is, generally, the term of the licence, unless there is a presumption of renewal at negligible cost. Using the licence term reflects the period over which the Group will receive economic benefit. For technology specific licences with a presumption of renewal at negligible cost, the estimated useful economic life reflects the Group’s expectation of the period over which the Group will continue to receive economic benefit from the licence. The economic lives are periodically reviewed, taking into consideration such factors as changes in technology. Historically, any changes to economic lives have not been material following these reviews.

Customer bases

The estimated useful life principally reflects management’s view of the average economic life of the customer base and is assessed by reference to customer churn rates. An increase in churn rates may lead to a reduction in the estimated useful life and an increase in the amortisation charge. Historically, changes to the estimated useful lives have not had a significant impact on the Group’s results and financial position.

Capitalised software

The useful life is determined by management at the time the software is acquired and brought into use and is regularly reviewed for appropriateness. For computer software licences, the useful life represents management’s view of expected benefits over which the Group will receive benefits from the software, but not exceeding the licence term. For unique software products controlled by the Group, the life is based on historical experience with similar products as well as anticipation of future events, which may impact their life, such as changes in technology. Historically, changes in useful lives have not resulted in material changes to the Group’s amortisation charge.

Property, plant and equipment

Property, plant and equipment also represent a significant proportion of the asset base of the Group, being 12.6% (2008: 13.1%) of the Group’s total assets. Therefore, the estimates and assumptions made to determine their carrying value and related depreciation are critical to the Group’s financial position and performance.

Estimation of useful life

The charge in respect of periodic depreciation is derived after determining an estimate of an asset’s expected useful life and the expected residual value at the end of its life. Increasing an asset’s expected life or its residual value would result in a reduced depreciation charge in the consolidated income statement.

The useful lives and residual values of Group assets are determined by management at the time the asset is acquired and reviewed annually for appropriateness. The lives are based on historical experience with similar assets as well as anticipation of future events, which may impact their life, such as changes in technology. Furthermore, network infrastructure is only depreciated over a period that extends beyond the expiry of the associated licence under which the operator provides telecommunications services, if there is a reasonable expectation of renewal or an alternative future use for the asset.

Historically, changes in useful lives and residual values have not resulted in material changes to the Group’s depreciation charge.